1. Field of the Invention
The invention relates to a vehicle wheel with a wheel rim and a wheel disc, whereby the wheel disc is connected to the wheel rim by means of at least one connecting element that is guided in a passage in the rim base and is joined in the wheel disc.
The invention also relates to a method for producing the connection between the wheel rim and the wheel disc of the vehicle wheel.
The vehicle wheel is used for all types of motorised vehicles, in particular as a lightweight-construction vehicle wheel for passenger cars and motorcycles.
The wheel disc may be designed as a wheel spider with spokes (spoke wheel) or as a largely closed-surface wheel disc.
2. Discussion of Background Information
One device of this type is known from the printed publication US 2004/0021365 A1. With this vehicle wheel a star-shaped wheel disc (wheel spider, spoke unit) is joined to the wheel rim by means of several connecting elements which are designed as countersunk blind rivets or countersunk bolts.
The connecting elements lead from the rim outer side of the wheel rim through—in each case—one through-hole in the well of the rim base and, on the inner side of the rim, are riveted or screwed to the adjacent spoke unit.
The connecting elements, in order to facilitate the fitting of the tire, have a head which has a very flat design and in the joined state is arranged recessed, largely flush with the contour of the rim base on the outer side of the rim.
The countersunk blind rivets consist—for the purpose of connecting deformation—of soft material, so that with these connecting elements specifically only small forces can be transmitted. In addition, after their installation, notching fracture points remain in the countersunk head from the detached rivet mandrel.
The countersunk bolts each have, for their installation, an auxiliary geometry for the installation tool to engage with, which is designed as a hexagon socket in the countersunk head.
These countersunk bolts are weakened in their cross section through the integrated auxiliary geometry. The tapering of the cross section of the connecting element in the area of the head let into the rim base reduces the forces that can be transmitted with the connecting element, which weakens the connection particularly under the continuous load acting on the vehicle wheel.
Over and above this, this auxiliary geometry of the countersunk bolts, like the rivet mandrel fracture point, generates a notching effect, which additionally reduces the strength of the connecting element.
This, in the event of large alternating loads, particularly with misuse loads, can lead to the premature breakage of the connecting element and thereby of the connection.
If—in order to counteract this—connecting elements with a larger cross section are used, this results in an undesirably larger space requirement for the connection in the rim base and to an undesirably greater vehicle wheel mass.
Furthermore, a large cross section, in particular of the head, regularly results in a contour projecting beyond the rim base, at least, however, to an inhomogeneous pattern of the contour of the rim base, which hampers the fitting of the tire and, over and above this, carries with it the danger of damaging the tire.